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0N/A<
a name="id2476275"></
a><
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div class="refnamediv">
0N/A<
p>lwres_lwpacket_renderheader, lwres_lwpacket_parseheader — lightweight resolver packet handling functions</
p>
0N/A<
div class="refsynopsisdiv">
0N/A<
div class="funcsynopsis">
0N/A<
table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0" style="padding-bottom: 1em">
0N/A<
td><
code class="funcdef">
0N/A<
b class="fsfunc">lwres_lwpacket_renderheader</
b>(</
code></
td>
0N/A<
td>lwres_buffer_t *�</
td>
0N/A<
var class="pdparam">b</
var>, </
td>
0N/A<
td>lwres_lwpacket_t *�</
td>
0N/A<
var class="pdparam">pkt</
var><
code>)</
code>;</
td>
0N/A<
table border="0" summary="Function synopsis" cellspacing="0" cellpadding="0">
0N/A<
td><
code class="funcdef">
0N/A<
b class="fsfunc">lwres_lwpacket_parseheader</
b>(</
code></
td>
0N/A<
td>lwres_buffer_t *�</
td>
0N/A<
var class="pdparam">b</
var>, </
td>
0N/A<
td>lwres_lwpacket_t *�</
td>
0N/A<
var class="pdparam">pkt</
var><
code>)</
code>;</
td>
0N/A<
div class="refsect1" lang="en">
0N/A<
a name="id2543390"></
a><
h2>DESCRIPTION</
h2>
0N/A These functions rely on a
0N/A <
span class="type">struct lwres_lwpacket</
span>
0N/A<
pre class="programlisting">
0N/Atypedef struct lwres_lwpacket lwres_lwpacket_t;
0N/A<
pre class="programlisting">
0N/Astruct lwres_lwpacket {
0N/A lwres_uint32_t length;
0N/A lwres_uint16_t version;
0N/A lwres_uint16_t pktflags;
0N/A lwres_uint32_t serial;
0N/A lwres_uint32_t opcode;
0N/A lwres_uint32_t result;
0N/A lwres_uint32_t recvlength;
0N/A lwres_uint16_t authtype;
0N/A lwres_uint16_t authlength;
0N/A The elements of this structure are:
0N/A<
div class="variablelist"><
dl>
0N/A<
dt><
span class="term"><
code class="constant">length</
code></
span></
dt>
0N/A the overall packet length, including the entire packet header.
0N/A This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
0N/A<
dt><
span class="term"><
code class="constant">version</
code></
span></
dt>
0N/A the header format. There is currently only one format,
0N/A <
span class="type">LWRES_LWPACKETVERSION_0</
span>.
0N/A This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
0N/A<
dt><
span class="term"><
code class="constant">pktflags</
code></
span></
dt>
0N/A library-defined flags for this packet: for instance whether the
0N/A is a request or a reply. Flag values can be set, but not defined
0N/A This field is filled in by the application wit the exception of
0N/A LWRES_LWPACKETFLAG_RESPONSE bit, which is set by the library in
0N/A lwres_gabn_*() and lwres_gnba_*() calls.
0N/A<
dt><
span class="term"><
code class="constant">serial</
code></
span></
dt>
0N/A is set by the requestor and is returned in all replies. If two
0N/A packets from the same source have the same serial number and are
0N/A the same source, they are assumed to be duplicates and the
0N/A This field must be set by the application.
0N/A<
dt><
span class="term"><
code class="constant">opcode</
code></
span></
dt>
1777N/A Opcodes between 0x00000000 and 0x03ffffff are
0N/A reserved for use by the lightweight resolver library. Opcodes
0N/A 0x04000000 and 0xffffffff are application defined.
0N/A This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
1777N/A<
dt><
span class="term"><
code class="constant">result</
code></
span></
dt>
0N/A is only valid for replies.
0N/A Results between 0x04000000 and 0xffffffff are application
0N/A Results between 0x00000000 and 0x03ffffff are reserved for
0N/A This field is filled in by the lwres_gabn_*() and lwres_gnba_*()
0N/A<
dt><
span class="term"><
code class="constant">recvlength</
code></
span></
dt>
0N/A is the maximum buffer size that the receiver can handle on
0N/A and the size of the buffer needed to satisfy a request when the
0N/A is too large for replies.
0N/A This field is supplied by the application.
1777N/A<
dt><
span class="term"><
code class="constant">authtype</
code></
span></
dt>
0N/A defines the packet level authentication that is used.
0N/A Authorisation types between 0x1000 and 0xffff are application
0N/A and types between 0x0000 and 0x0fff are reserved for library
0N/A Currently these are not used and must be zero.
1777N/A<
dt><
span class="term"><
code class="constant">authlen</
code></
span></
dt>
0N/A gives the length of the authentication data.
0N/A Since packet authentication is currently not used, this must be
0N/A The following opcodes are currently defined:
0N/A<
div class="variablelist"><
dl>
0N/A<
dt><
span class="term"><
code class="constant">NOOP</
code></
span></
dt>
0N/A Success is always returned and the packet contents are echoed.
0N/A The lwres_noop_*() functions should be used for this type.
0N/A<
dt><
span class="term"><
code class="constant">GETADDRSBYNAME</
code></
span></
dt>
0N/A returns all known addresses for a given name.
0N/A The lwres_gabn_*() functions should be used for this type.
0N/A<
dt><
span class="term"><
code class="constant">GETNAMEBYADDR</
code></
span></
dt>
0N/A return the hostname for the given address.
0N/A The lwres_gnba_*() functions should be used for this type.
<
p><
code class="function">lwres_lwpacket_renderheader()</
code>
transfers the contents of lightweight resolver packet structure
<
span class="type">lwres_lwpacket_t</
span> <
em class="parameter"><
code>*pkt</
code></
em> in
network byte order to the lightweight resolver buffer,
<
em class="parameter"><
code>*b</
code></
em>.
<
p><
code class="function">lwres_lwpacket_parseheader()</
code>
performs the converse operation. It transfers data in network
byte order from buffer <
em class="parameter"><
code>*b</
code></
em> to resolver
packet <
em class="parameter"><
code>*pkt</
code></
em>. The contents of the buffer
<
em class="parameter"><
code>b</
code></
em> should correspond to a
<
span class="type">lwres_lwpacket_t</
span>.
<
div class="refsect1" lang="en">
<
a name="id2543707"></
a><
h2>RETURN VALUES</
h2>
<
code class="function">lwres_lwpacket_renderheader()</
code> and
<
code class="function">lwres_lwpacket_parseheader()</
code> return
<
span class="errorcode">LWRES_R_SUCCESS</
span>. If there is insufficient
space to copy data between the buffer <
em class="parameter"><
code>*b</
code></
em> and
lightweight resolver packet <
em class="parameter"><
code>*pkt</
code></
em> both
return <
span class="errorcode">LWRES_R_UNEXPECTEDEND</
span>.